CVE-2026-3889 — MEDIUM (6.5)

Q: What is CVE-2026-3889?

CVE-2026-3889 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

Q: How severe is CVE-2026-3889?

CVE-2026-3889 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-3889?

Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Thunderbird.

Vulnerability Description

Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

NONE

Integrity

HIGH

Availability

NONE

Affected Products

Vendor	Product	Versions
Mozilla	Thunderbird	< 140.9.0

Related Weaknesses (CWE)

CWE-451

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2020723Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-23/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-24/Vendor Advisory

FAQ

What is CVE-2026-3889?

CVE-2026-3889 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

How severe is CVE-2026-3889?

CVE-2026-3889 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-3889?

Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Thunderbird.